Actually the little USB chargers charge in parallel (meaning they all charge at the same time instead of one after the other), but unlike a parallel charge board they are completely separate and isolated charge circuits without any connection to the other battery sockets on the charger. As far as chargers go you might look at Hota and iSDT, they both make good chargers and there are a few models that are AC powered, but some are only DC powered and would need a separate power supply or a big car/boat battery to run them and you will likely need a few special cables to hook things up depending on what the output of the charger is (many are XT60 now) and what the input to the parallel boards are (some are XT60, some are Banana plug). This is not easy to pick just one, and a decent charger/parallel boards are not super cheap, I think you will need to look around at what is available and decide what you will want/need. There are not many 1s and 2s parallel boards so I am not sure there is a great answer for what you are looking for. To charge my 1s-6s packs I have 4 parallel boards and 2 charging cables plus a few different adapter plugs/cables. You need to look at the different types of connectors you have on your batteries and try to find something that will work for each, it isn't easy or cheap, you will likely spend around $250 dollars for all the stuff you may need. I am sure others may chime in here with some options, and I will look online later to see what new may have come out for you.